Disambiguation in spatial navigation with theta phase coding

It is an open question whether the hippocampal cognitive map is useful for navigation with ambiguity in space representation. The hippocampus might need to assign different contexts to cell populations in the same place, according to the traditional rate coding scheme. Recent experimental observations on theta phase precession, the theta rhythm-dependent activity in the hippocampus, demonstrate that behavioral sequences are represented in a compressed form in the theta cycle, suggesting the possibility of phase coding of context-dependent information in the hippocampus.Here we elucidated memory-guided locomotor behaviors by a hippocampal model with theta phase coding. We hypothesized that current sensory input, spatial memory and motion are concurrently coded in the phase of every theta cycle to compute a possible direction of motion. Computer experiments demonstrated that our simple model of the hippocampal-locomotor system with theta phase coding can generate context-dependent behavioral information.